The impact of system test benches on the development and validation of wind energy converters is significantly increasing, and that is due to the higher availability as well as the provided powerful actuator and emulation systems. However, the question remains to be answered about how consistent measurements in the laboratory are. Especially in the case where no field measurements are available for prototypes. The challenge in this regard is the unknown accuracy of simulations and the lack of an experimentally calibrated torque measurement in the hardware-in-the-loop (HiL) setup. The presented paper handles this topic and presents an evaluation method to elaborate measurement consistency independent from field tests. A transparent and comprehensive comparison is provided, taking advantage of the deterministic test environment enabled by the HiL system and the dedicated designed torque measurement adapter. Provided results demonstrate consistent measures obtained from the real-time simulation, HiL control system, and the electrical and mechanical measurements, where a low deviation of up to 2 % is partly observed.

Modern wind turbines have some of the highest levels of torque and non-torque loads of all industrial sectors. These high loads present a great challenge for the design of wind turbines. On a nacelle test bench, the wind turbine drivetrain can be tested and validated against the design. It is therefore important to measure the correct level of each load and all its dynamic behaviors during the test. The best way to achieve this is to measure the loads directly in front of the drivetrain. This paper presents a method of direct load measurement on the shaft adapter which connects the drivetrain to the test bench. The technical solution and some important details about the instrumentation on the adapter are also presented. Methods of signal nulling as well as signal conversion from raw signals to the loads are compared as well. The measurements obtained are then compared with the applied loads from the test bench which show good agreement. As a special case, the torque measurement is validated and calibrated up to 5 MN m by means of a state-of-the-art torque transducer.